It is known that an audio mixer system may be advantageously used to edit several audio channels provided by several multi-channel devices such as video tape recorders (VTRs). In a typical configuration, several audio channels are input to an audio follow video mixer. The mixer can then be used to process the input audio channels according to various operations such as PREVIEW/REVIEW or FADE UP/FADE DOWN. Audio channels which are actively being processed may be monitored and output to other VTRs associated with the mixer.
In order to facilitate these various mixer operations, it has been found useful to provide several different operating modes for the mixer. For example, the mixer may be set to operate in an EDITOR mode in which an operator controls editor operations by use of video editor which provides various control signals to a mixer unit. In this mode, most of the mixer's local controls, which may be located on the mixer's console, will be disabled. The mixer may also be set to operate in AUTO mode wherein various functions are initiated by the operator locally using the mixer console but are performed automatically by the mixer according to preset operating routines.
In addition to these functions, a mixer may also be set for MANUAL mode operation. In this mode, the operator manually controls the various operations of the mixer using local controls located on the mixer console. For example, the operator may perform crossfades manually between selected audio channels. Manual control of the crossfade operation affords the operator the advantage of tailoring the manner in which the crossfade is performed, rather than being constrained to a particular preprogrammed crossfade.
However, prior art mixer systems in which crossfades are performed manually suffer the drawback that it is difficult for the operator to identically reproduce a particular crossfade operation. While an experienced operator may minimize this drawback by repeated practice, this requires additional time and expense in production.
There is therefore a need to provide a mixer which offers the flexibility afforded by manual operation along with ease in reproducing custom crossfades.